A pile foundation carries the building load through weak or compressible upper soils down to competent bearing strata below. On Ontario industrial sites, piles are what you use when a conventional footing would settle, heave, or need to go uneconomically deep.
When an industrial building needs piles
A rigid frame steel building concentrates its entire load into a small number of column bases. A 40 m clear-span frame at 9 m bay spacing puts very large vertical and horizontal reactions into each base plate, and those reactions have to go somewhere competent. Where the upper soil cannot take them, you go deeper.
The geotechnical report decides this, not the builder and not the steel supplier. Standard penetration test values, soil classification and groundwater level across the footprint determine whether a shallow foundation is viable. Commission it before you finalise the building footprint, it is the cheapest document on the project and the one that most often changes the design.
Pile types used on Ontario industrial sites
The choice is driven by soil profile, load, site access and schedule. Helical piles install quickly with small equipment and no spoil; driven piles reach higher capacities; caissons suit very high loads and sites where a large-diameter shaft can be socketed into rock or dense till.
How piles connect to the rest of the building
Piles rarely support the structure directly. A reinforced concrete pile cap or grade beam spans between them and distributes the column reaction across the pile group, which is why the foundation and superstructure have to be designed together rather than tendered separately.
The connection detail that causes the most trouble is the anchor bolt group. Pre-engineered rigid frames arrive with base plates drilled to a fixed pattern, and the tolerance for setting those bolts is tight. Getting it right requires the frame reactions and the bolt template in hand before the concrete is placed, one of the practical reasons single-contract delivery is faster than assembling the trades yourself.
| System | Typical working capacity | Installed by | Suits |
|---|---|---|---|
| Helical (screw) piles | 50–250 kN | Hydraulic torque head, compact rig | Restricted access, fast turnaround, lighter industrial and addition work; no spoil |
| Driven steel pipe / H-pile | 300–1,500 kN | Impact or vibratory hammer | Higher loads, deep competent strata, sites tolerant of driving vibration |
| Augered cast-in-place | 400–2,000 kN | Continuous flight auger | Cohesive soils, vibration-sensitive neighbours, high volume |
| Drilled caisson / belled pier | 1,000 kN and above | Drill rig, belling tool | Very high concentrated loads, socketing into dense till or rock |
Indicative ranges for planning only. Pile type, capacity and depth for any specific building are set by the geotechnical and structural engineers of record.